Kattis keeps giving me a Runtime Error on heliocentric

Question

Kattis gives me a Runtime Error for heliocentric upon submission. I changed parts of the code and asked my friends and we all have no idea what is wrong. Does anyone have an idea as to what I am missing?

import java.util.Scanner;

public class heliocentric {

  public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);
    int inE;
    int inM;
    boolean collin;
    int days;

    for (int i = 1; i < 10; i++) {
      days = 0;
      collin = false;
      inE = scan.nextInt();
      inM = scan.nextInt();
      if (inE < 0 || inM < 0) {
        collin = true;
      }

      while (collin != true) {
        if (inE == 0 && inM == 0) {
          break;
        }
        inE++;
        if (inE == 365) {
          inE = 0;
        }
        inM++;
        if (inM == 687) {
          inM = 0;
        }
        days++;
        if (inE == 0 && inM == 0) {
          collin = true;
        }
      }
      System.out.println("Case " + i + ": " + days);
    }
    scan.close();
  }
}

Input

0 0
364 686
360 682
0 1
1 0

Output

Case 1: 0
Case 2: 1
Case 3: 5
Case 4: 239075
Case 5: 11679

Answer 1

Your logic is OK, but your I/O isn't, which is often the problem with Kattis submissions.

The description says "at most 10" but the first test case only has 5 lines of input, so your code will probably throw a java.util.InputMismatchException.

You can use the following pattern to exit cleanly:

var scanner = new java.util.Scanner(System.in);

while (scanner.hasNextInt()) {
    // read the ints
}

scanner.close();

...or slap a try/catch around your code. That's ugly, but works as a quick way to test a hypothesis.

As an aside, variables with names like collin are confusing. This variable isn't necessary; just break as soon as you're done with the loop instead of adding more state to have to manage.

There's no need to forward-declare variables. Declare them where you use them, as tightly scoped as possible. This reduces the mental burden it takes to understand the code.

Cleaner:

public class heliocentric {
    public static void main(String[] args) {
        var scanner = new java.util.Scanner(System.in);

        for (int i = 1; scanner.hasNextInt(); i++) {
            int days = 0;
            int e = scanner.nextInt();
            int m = scanner.nextInt();

            while (e != 0 || m != 0) {
                e = (e + 1) % 365;
                m = (m + 1) % 687;
                days++;
            }

            System.out.println("Case " + i + ": " + days);
        }

        scanner.close();
    }
}

There's probably a better mathematical solution to this problem...